The invention relates to a color filter substrate and a manufacturing method thereof.
Liquid crystal displays (LCDs) have the advantages, such as small volume, low power consumption, no radiation, and relatively low product cost. LCDs have experienced a fast development in recent ten years, and there are great progresses either in the size of the screen and/or in the display quality. With the development of LCDs, the competition between the manufacturers is becoming fierce. As the manufacturers enhance the product performance continuously, they also try to decrease the product cost so as to enhance the competition power.
A color filter substrate is a main component and important for a LCD, and the quality and the cost of the color filter substrate directly exert an influence on the quality and the cost of a LCD. Therefore, enhancing quality of a color filter substrate and decreasing cost of a color filter substrate are the main development directions for the manufacturers. Decreasing product cost of a color filter substrate mainly includes decreasing the numbers of processes, decreasing the times for lithography, increasing the produce efficient, and the like.
Currently, in producing a color filter substrate, a four-step lithography process may be employed. In the four-step lithography process, four cycles of film making, lithography, and etching processes are performed, so as to prepare a black matrix, a red pixel region, a green pixel region, and a blue pixel region on a substrate. Finally, for example, indium tin oxide (ITO) is deposited on the substrate, and the color filter substrate is prepared. The specific processes are described as follows.
First, a layer of chromium oxide (CrOx) thin film or chromium (Cr) thin film as the material for the black matrix is deposited on a glass substrate, and then a layer of photoresist is applied on the thin film. Then, the pattern transferring from a mask to the photoresist is completed through a lithography process, and then the desired pattern is formed on the CrOx thin film or Cr thin film by the etching and lifting-off processes (the black matrix is formed in this step). Through three “deposition-lithography-etching” processes, red (RGB: 255, 0, 0), green (RGB: 0, 255, 0), and blue (RGB: 0, 0, 255) patterns are formed on the glass substrate, and finally with depositing an indium tin oxide (ITO) thin film as a common electrode, the traditional color filter substrate is prepared. The different methods for forming the color resin films can be classified as dying method, electrophoretic deposition method, dye dispersion method, printing method, and the like.
The conventional method of preparing a color filter substrate includes four cycles of film forming, lithography, and etching processes, which is of relatively low product efficiency and relatively high product cost. Meantime, since dye distribution uniformity is limited, the conventional method for forming the color resin films is difficult to obtain stability of color in mass production.